If you want to go a little further south into Tierra del Fuego, Ushuaia is a great trip and the Fuegian lamb almost makes the trip worth it by itself. Both LAN and Aerolineas run this route.

Calafate is also a nice destination if you are interested in seeing a glacier up close and personal. Aerolineas runs several daily flights from AEP, and believe at least one daily flight direct from EZE. You might want to research that. From AEP, you will likely connect once in Trelew.